The invention concerns a displacer assembly for a clip machine, in particular a sausage clip machine. In particular the invention concerns a displacer assembly for a clip machine, in particular a sausage clip machine, which includes: at least a first pair of displacer shears and a second pair of displacer shears arranged parallel thereto, wherein the displacer shears are reversibly movable towards each other to constrict the filled packaging casing to form a filling material-free plaited end portion. In that case the first pair of displacer shears comprises two displacer shears which are at least approximately identical in minor image relationship. The second pair of displacer shears has a first displacer shear which is at least approximately identical to the displacer shears of the first pair of displacer shears and a second shorter displacer shear.
A clip machine of the kind set forth hereinbefore, which is known for example from German patent specification No 25 50 042, is typically used to close packaging casings in bag or tubular form and filled with liquid to thick-pasty or also (in part) granular content. Firstly in that procedure the filling material is introduced into the packaging casing and—in the case of a tubular packaging casing—thereafter divided up into portions (sausages) by means of the for example pairs of displacer shears of the displacer assembly. The pairs of displacer shears which are arranged pivotably about a common axis in a radial direction or transversely with respect to the conveyor direction of the filling material constrict the packaging casing for that purpose and displace the filling material which is in the constriction region in the axial direction or in the conveyor direction of the filling material. A filling material-free tubular plaited portion is thus formed in the constriction region. In the next working cycle a closure clamp or clip or, in the case of a double clip arrangement, two closure clamps or clips are applied to the tubular plaited portion formed in that way, by means of the above-described closure tools which are movable relative to each other. If the product in sausage form is to be suspended for example on a smoking bar for further transport or for further processing, a suspension element such as a loop of thread is introduced into one of the closure clips and fixed to the closure clip at the tubular plaited portion. After the product in sausage form has been closed by fitment of closure clamps or clips the pairs of displacer shears are moved away from each other and permit the product in sausage form to pass through.
European patent application No 1 886 573 (US 20080085668) discloses a clip machine in which the displacer assembly has displacer shears which, for constriction of the filled packaging casing, are reversibly movable towards each other along a linear guide.
In practice it is further known that, in particular in the production of products in sausage form with a suspension element, which immediately after production are to be automatically placed by means of their suspension element on a suspension arrangement, the lower displacer shear of the pair of displacer shears which faces in the conveyor direction of the filling material is shorter than the other displacer shears. That shortening of that displacer shear is necessary in order to release the suspension element which is disposed in the otherwise closed structure of the displacer shears and which is held by the closure clip between the displacer shears and the catch device in the conveyor direction downstream of the displacer shears.
Those previously known clip machines however suffer from disadvantages. Thus it is not possible to exclude the possibility that the shortened displacer shear, particularly when the products in sausage form are of large diameters and/or when dealing with delicate packaging casings, penetrates into the packaging casing during the constriction procedure and thus form a fold which can no longer be engaged by the closure clip. It is also not possible to exclude damage to the packaging casing.
The object of the present invention is to overcome the above-indicated disadvantages and to provide a displacer assembly for a clip machine, which makes the closure procedure a more reliable process.